Furnace



Feb. 26, 1946. J. A. ULBERG Filed April]. 25. 1 .94. 4

mm? ll/er Patented Feb. 26, 1946 UNITED STATES PATENT OFFICE 5 Y FUR NACE- John A. Ulberg, Sioux Falls, S.Dak. Application April 25, 1944,seria1 No. 532,636

1 Claim. 01. 12699) This invention relates to furnaces, and has particular reference to improvements in furnaces of the general type comprising an inner shell or casing enclosing a combustion chamber and an outer shell or casing surrounding or enclosing said inner shell or casing and cooperating therewith to define therebetween a chamber wherein air or water is heated by radiation of heat from the combustion chamber for conduction to desired points by suitable pipes or conduits leading from the outer shell or casing.

One special and important object of the invention is to provide a furnace of the general type mentioned embodying an inner shell or casing of novel form designed to afford an exceptionally large heat radiating area whereby high heating efliciency is obtained from fuel' consumed in the combustion chamber.

Another special and important object of the invention is to provide a furnace of the general type mentioned embodying an inner shell or casing of novel form and a novel arrangement .of the firebox or oil or gas burner or burner nozzle, as the case may be, and of a gas outlet flue, relative to said inner shell and relative to each other, whereby high heating efliciency is obtained from fuel consumed in the combustion chamber.

Another special and important object of the invention is to provide a furnace of the type mentioned embodying the features of the invention and which is of simple practical construction and of low production cost.

With the foregoing and other objects in view, which will become more fully apparent as the nature of the invention is better understood, the same consists in a furnace embodying the novel features of construction, combination and arrangement of parts as will be hereinafter more fully described and defined in the appended claims.

In the accompanying drawing, wherein like characters of reference denote corresponding parts in the different views:

Figure 1 is a perspective view of a furnace constructed in accordance with one practical embodiment of the invention, the outer casing being broken away to show the interior construction.

' Figure 2 is a vertical section on the line 2-2 of Figure 1; and

Figure 3 is a horizontal section on the line 3-3 of Figure 2.

Referring to the drawing in detail, it will be observed that the present furnace is of the general type comprisingan inner shell -or 'casing Ill enclosing a combustion chamber a, and an outer shell or casing H surrounding or enclosing said inner shell or casing and cooperating therewith to define therebetween a chamber b to contain a fluid, such as air or water, to be heated. g r a Both of the'shells or casings l0 and H may beformed in any suitable manner from any suitable material and may be of any desired sizes and shapes. Moreover, any suitable means such as an oil or gas burner l2 or, alternatively, a firebox for burning coal or like fuel may be provided entirely or in part within the combustion chamber a for heating said chamber, and a flue I3 is provided for outlet of combustion gases from said chamber. V V

Preferably the inner casing l0 and the combustion chamber a are of narrow, elongated form and are upwardly tapered. Preferably, too, the. oil or gas burner or firebox l2, as the case may be, is disposed as low' as practicable in the combustion chamber a, and the flue I3 is disposed as high as practicable in said combustion chamber, whereby the combustion gases are required to travel substantially from bottom to top of said combustion chamber before they escape therefrom through the flue l3. Moreover, the side walls M of the casing l0 preferably are corrugated as indicated at IE to afford a large area for exchange of heat from the combustion chamber a to the chamber b and said corrugations 15, considered lengthwise, preferably extend vertically so that the upwardly flowing gases may pass freely through substantially all portions of all of the same. Furthermore, the flue I3 preferably extends horizontally or substantially horizontally from end i to end of the combustion chamber a and has therein a comparatively narrow, elongated slot l6 extending longitudinally thereof and opening preferably through the top thereof to insure substantially uniform distribution of the combustion gases throughout the combustion chamber. In other words, while the area of the slot I 6 preferably is as great as the cross sectional area of the flue l3, said slot preferably is of such narrow width as to preclude the possibility of all of the combustion gases escaping through any short-length portions of the same. Therefore, the combustion gases distribute themselves along the length of said slot, which preferably is substantially co-extensive in length with the combustion chamber a. and, as a consequence, the gases are distributed substantially The corrugated side walls 14 of the innershell or casing It! may be in direct interfitting engagement with each other at their upper ends where they may be welded or otherwise suitably fastened directly together, or the said upper ends of said side walls may be spaced apart and connected together by a cap-piece I! to which they may be welded or otherwise suitably fastened.- In either case, the end walls l8 of said inner shell or casing may be formed either as integral parts of, the side walls II thereof, or separately from said side walls to which they may be welded or otherwise suitably secured.

Preferably the fiue'l3 extends entirely through the chambers a and b and is closed at one end, exteriorly of the outer shell or oasinglhby a cap. lilwhich preferably isremovable to afford ready access to said flue for the purpose of cleaning the same or for'any other desired purpose.

-Within the flue l3 may be arranged a pipe or coil 2'!) to contain water or other fluid tobe heated by hotgases flowing through said flue, said coil 20 comprising, for example, part of a hot water supply system of a, dwelling or the like and being used particularly when the furnace is of the type in which air is heated in the chamber b.

Welded or other suitable joints may be provided between the flue l3 and the shells or casings l0 and H at the points where said flue extends through said shells or casings. while at its bottom the shell or casing l0 may be closed in any suitable manner as by a plate 2|.

Due to the described construction of the present furnace it has been found that high advantage is obtained from fuel consumed. At the same time, said furnace obviously is of simple construction and may be produced at comparatively low cost.

From the foregoing description considered in connection with the accompanying drawing, it is believed that the construction and operation of the furnace will be clearly understood and its advantages appreciated. It is desired to point out, however, that while only a single specific structural embodiment of the invention has been illustrated and described, the same is readily capable of specifically diiferent structural embodiments within its spirit and scope as defined in the appended claim;

I claim:

A furnace comprising a combustion chamber having a bottom wall, end walls, a top wall and upwardly converging corrugated side walls, an outer casing'enclosing the combustion chamber in spaced relation thereto so as to define therebetweena chamber to contain a fluid to be heated, means for interiorly heating the combustion chamber, the corrugationsof the side walls of the combustion chamber considered lengthwise extending vertically through said top and bottom walls thereof so as to provide for free upward flow of hot gases through the combustionchamber and to afiord a large area for exchange of heat from the combustion chamber to said fluid-containing chamber, and a flue for outlet of combustion gases extending throughrthe' combustion chamber and wholly supported by the end walls of the latter in spaced relation to the top, bottom and sides thereof, said flue having an elongated upwardly facing slotextending'longitudinally thereof, said slot having its ends terminating spaced from the end walls of the combustion chamber for entrance into the same of combustion gases from said com- 

